Voice over Internet Protocol (VoIP) is a method for the real-time exchange of speech and other audio over the Internet and other networks. Audio may be converted into digital form, broken up into units of data called packets, and transmitted across a network. Upon receipt, the packets are assembled, and the audio may be converted from digital form to analog form and played.
VoIP calls may be made by several methods. In one method, a call is placed from a standard telephone which is connected to a computer with an analog telephone adapter. The adapter converts sound into digital form for transmission over a network. In a second method, a call is made from an IP phone. The IP phone may convert audio to digital form. The IP phone may connect directly to an Ethernet port for transmission of the digital audio across a network. A third method is from a computer. The computer may include equipment for processing sound, such as a microphone to capture sound, a sound card to convert the sound to digital form, and speakers to play the sound. The computer may be connected to a network for transmission of the sound.
VoIP calls may be made in several settings. A VoIP call may be limited to one participant at each end. A VoIP call may be a conference call, with multiple participants. In addition, a VoIP call may be part of a chat conference. Chat conferences are the real-time exchange of text among groups of people.
Under current VoIP systems, retrieval of VoIP calls, for replaying or forwarding, may be difficult or impossible. In some systems, calls may be automatically deleted once they are received or placed. In other systems, the calls may be retained but may be difficult or impossible to retrieve.